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/*
* BIRD Library -- Event Processing
*
* (c) 1999 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
/**
* DOC: Events
*
* Events are there to keep track of deferred execution.
* Since BIRD is single-threaded, it requires long lasting tasks to be split to smaller
* parts, so that no module can monopolize the CPU. To split such a task, just create
* an &event resource, point it to the function you want to have called and call ev_schedule()
* to ask the core to run the event when nothing more important requires attention.
*
* You can also define your own event lists (the &event_list structure), enqueue your
* events in them and explicitly ask to run them.
*/
#include "nest/bird.h"
#include "lib/event.h"
event_list global_event_list;
event_list global_work_list;
inline void
ev_postpone(event *e)
{
if (ev_active(e))
{
rem_node(&e->n);
e->n.next = NULL;
}
}
static void
ev_dump(resource *r)
{
event *e = (event *) r;
debug("(code %p, data %p, %s)\n",
e->hook,
e->data,
e->n.next ? "scheduled" : "inactive");
}
static struct resclass ev_class = {
"Event",
sizeof(event),
(void (*)(resource *)) ev_postpone,
ev_dump,
NULL,
NULL
};
/**
* ev_new - create a new event
* @p: resource pool
*
* This function creates a new event resource. To use it,
* you need to fill the structure fields and call ev_schedule().
*/
event *
ev_new(pool *p)
{
event *e = ralloc(p, &ev_class);
return e;
}
/**
* ev_run - run an event
* @e: an event
*
* This function explicitly runs the event @e (calls its hook
* function) and removes it from an event list if it's linked to any.
*
* From the hook function, you can call ev_enqueue() or ev_schedule()
* to re-add the event.
*/
inline void
ev_run(event *e)
{
ev_postpone(e);
e->hook(e->data);
}
/**
* ev_enqueue - enqueue an event
* @l: an event list
* @e: an event
*
* ev_enqueue() stores the event @e to the specified event
* list @l which can be run by calling ev_run_list().
*/
inline void
ev_enqueue(event_list *l, event *e)
{
ev_postpone(e);
add_tail(l, &e->n);
}
/**
* ev_schedule - schedule an event
* @e: an event
*
* This function schedules an event by enqueueing it to a system-wide
* event list which is run by the platform dependent code whenever
* appropriate.
*/
void
ev_schedule(event *e)
{
ev_enqueue(&global_event_list, e);
}
/**
* ev_schedule_work - schedule a work-event.
* @e: an event
*
* This function schedules an event by enqueueing it to a system-wide work-event
* list which is run by the platform dependent code whenever appropriate. This
* is designated for work-events instead of regular events. They are executed
* less often in order to not clog I/O loop.
*/
void
ev_schedule_work(event *e)
{
if (!ev_active(e))
add_tail(&global_work_list, &e->n);
}
void io_log_event(void *hook, void *data);
/**
* ev_run_list - run an event list
* @l: an event list
*
* This function calls ev_run() for all events enqueued in the list @l.
*/
int
ev_run_list(event_list *l)
{
node *n;
list tmp_list;
init_list(&tmp_list);
add_tail_list(&tmp_list, l);
init_list(l);
WALK_LIST_FIRST(n, tmp_list)
{
event *e = SKIP_BACK(event, n, n);
/* This is ugly hack, we want to log just events executed from the main I/O loop */
if ((l == &global_event_list) || (l == &global_work_list))
io_log_event(e->hook, e->data);
ev_run(e);
tmp_flush();
}
return !EMPTY_LIST(*l);
}
int
ev_run_list_limited(event_list *l, uint limit)
{
node *n;
list tmp_list;
init_list(&tmp_list);
add_tail_list(&tmp_list, l);
init_list(l);
WALK_LIST_FIRST(n, tmp_list)
{
event *e = SKIP_BACK(event, n, n);
if (!limit)
break;
/* This is ugly hack, we want to log just events executed from the main I/O loop */
if ((l == &global_event_list) || (l == &global_work_list))
io_log_event(e->hook, e->data);
ev_run(e);
tmp_flush();
limit--;
}
if (!EMPTY_LIST(tmp_list))
{
/* Attach new items after the unprocessed old items */
add_tail_list(&tmp_list, l);
init_list(l);
add_tail_list(l, &tmp_list);
}
return !EMPTY_LIST(*l);
}
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